Viscosity-controlled regulator



NOV 10, 1942. R. G. DYKEMAN x-:T AL 2,301,665

VI SCOS ITY-CONTROLLED REGULATOR Filed May 19, 1938 2 Sheets-Sheet 1 3dfy VI SCOS ITY- CONTROLLED REGULATOR Filed May 19, 1958 2 Sheets-Sheet -2 Patented Nov. 10, 1942 OFFICE 2,391,665 vrscosm-com'aounn aacumroa l Reuben G. Dykeman and Joseph C. Shaw,

Dayton, Ohio Application Mayas, 193s, sei-lai No. 208,769

(ci. isi-104) 17 Claims.

This invention pertains to viscosity controned regulating or governing means wherein fluctuations of viscosity of a body of fluid is translated into motive force to effect various control or operating functions, and'the mode of operation thereof.

For illustrative purposes, but withno intent to unduly limit the scope or application of the invention, it is herein shown and described as applied to a thermal fluid conditioning apparatus wherein the variations of thermal influence is automatically controlled in accordance with liuctuations of fluid viscosity, and the method of operation, the illustrative embodiment being `a heat exchange unit for conditioning the lubricant supply of airplane, motor boat or racing' automobile engines, whereby chilled or congealed oil initially is brought quickly toproper lubricating consistency and thereafter the temperature influence so controlled and balanced as to maintain the Huid lubricant in a predetermined confdition of viscosity. It is to be understood, however, that the invention is not limited to such application but may be applied to various other purposes wherein automatic control of apparatus lin accordance with condition of viscosity of a governing duid is of primeimportance.

The present disclosure is a further development and amplicatlon of the apparatus and mode of operation forming the subject matter of copending application Serial No. 109,764, filed November 7, 1936, for Oil bypass device, to which cross reference is made.

The above mentioned application discloses means for automatically diverting the iiow'of i.;

lubricant or other uid through either Aof two alternate courses, in one of which the heat abheat exchange unit, whereupon the Lflow of lubricant is directed/ through the other of said courses wherein it is subject to the cooling influence of circulating air by which the heat is dissipated and the lubricant cooled. However, when flying at high altitudes and at great speed developed by modern airplanes, the air cooling influence may so far exceed that necessary to compensate for the heat absorbed by the lubricant during passage through the engine that the lubricant is cooled to too low degree-and its viscosity again increased, whereas the f ull cooling. capacity may be necessary at lower altitude and lesser speed. Therefore, in the present instance there isiprovided means for controlling the conditioning medium, whether air or other medium, in accordsorbed, while passing through the engine is .utilized to thaw congealed lubricant within the ance with fluctuations of viscosity cant. l

That is to say, whereasthe former construcol the lubri..

tion and mode of operation pertained primarily to the initial warming of the lubricant at the time of take-olf, in order that the engine might be supplied as quickly as possible with lubricant of proper viscosity, the present invention pertains to regulationpf the cooling influence toL maintain the lubricant in a predetermined condition of viscosity while in iiightor during the period of `operation subsequent to that contemplated in the former invention.

'I'he primary object of the invention is to utilize the iluctuations of 'viscosity of a duid body to govern operation of an associated apparatusby translating such viscosity iiuctuations into4 motive force to eiiect operating and control functions.

A further object of the invention is to provide a viscosity controlled regulating means for a heat exchange unit which is capable of being economically manufactured, which wlll be eicient in use, economical in operation, automatic in action, having relatively few operating parts and unlikely to get out of repair'.l

A further object of the invention is to provide viscosity controlled means for regulating the dow ofa separate iluid body in accordance with fluctuations of viscosity of a governing fluid.

A further object of the invention is to provide viscosity controlled means for regulating thermal conditioning medium of a heat exchange unit. f

A further object of the invention is to provide means for regulating the ilow of one body of iluld in accordance with iluctuations of viscosity of second body of uid.

A further object of the invention is to regulate the ilow4 of an air current in accordance with fluctuations of viscosity of a fluid body subject to the influence thereof.

A further object of the invention is to translate iluctuations oi' viscosity of a iiuid body into motive force for performance of extraneous control or operating functions.

A further object of the invention is to provide means for automatically maintaining a body of fluid at substantially constant viscosity.

A further object of the invention is to provide a fluid thermostatic control apparatus having the advantageousfeatures and meritorious characteristics herein mentioned.

A further object of the invention is to provide a device wherein there is created a pressure di!- system intermediate the source'of pressure and the oil temperature regulator, and wherein the back pressure resulting from the resistance to flow at4 that preselected point is utilized to control the viscosity of the oil.

With the above primary and other incidental objects in View as will more fully appear in the specification, the invention intended to be protected by Letters Patent consists of the features of construction, the i parts and combinations thereof, and the mode of operation, or their equivalents, as hereinafter described or illustrated l in the" accompanying drawings.

In the drawings, wherein is illustrated the pre- I- ferred but obviouslynot necessarily the only Fig. 2 le a horizontoiiseenonoi view of the escrocs ferential at a preselected point Vin the circulatory transfer of heat the condition of the iluid Within the unit is suillciently modified to permit less ref stricted flow therethrough.A The flowing warmed fluid is then subjected to cooling influence vof air circulated through the radiator unit to maintain culated through either passage of the unit is discharged to a suitable supply reservoir il from l which it is delivered to an engine or other point of operation and returned thence forI recirculation through one' path or the other of the conditioning apparatus according to the viscosity viscosity controlled governing mechanism shown in Fig. i.

rig. 3 illustrates e.' modiaed embodiment of the I invention.

Fig. als a detail sectional plan View of the shutter or damper means for the heat exchange oi reference throughout ,theseveral views.

While the invention is herein shown and de scribed as applied to control of viscosity condi' tions of engine lubricant circulated through a heat vexchange unit, it is to be understood that v this is merely one applicationof the invention and that itis otherwise applicable to a-wide variety of purposes.

In lieu of adjusting the series of air control shutters or dampers herein shown,

l the same viscosity control means may be .utilized .to adjust a valve controlling circulation 'of a heating medium or a'cooling or refrigerant medium asonditions may require.

Furthermore, although in the present instance lthe governing fluid is also the fluid to be conditioned, the invention contemplates useofa fluid condition of Viscosity.l The tube i9 has a reg Q stricted inlet orifice 22 through which the fluid subject to fluctuation of viscosity solely as a governing` mediumforlregulating an associated apparatus,or`for controlling the flow, thermal condition or other characteristics of a lsecond fluid body, or for operating a valve, electric switch,

' mechanical or electrical heater means. controlling chemical; reactions 'and various other applications, all within the purview of the invention and appended claims.

In the drawings lI indicates a heat exchange unit which is preferably of the air-cooled radiator type'having therein a'series ofbailles; 2 dening a tortuous path' through which fluid under pre'ssuremayow vfrom the intake 3 to the outlet '4. Surrounding-the unitis a warming jacket that if .the fluid ishighly viscous and congealed within the unit whereby -the flow thereof. is 'retarded, the flow of incomirlg fluid o f lower viscosity and higher temperature is automatically' directedthrough the warming Jacket, until by of the fluid. The circulation of the fluid through itsA respective coursesis controlled by a pair of iluidfpressure operated valves lll and i5 which respond respectively to Viscosity conditions of the f iuid being circulated. The valve i5 is a bypass relief valve which serves to permit the in* coming uid' under excess pressure to flow through the inlet E? and thence through -the warming'jjacket 5, whereby the congealed fluid in the main body of the radiator or heat eX- change unit is thawed and thermally reconditioned to accelerate its vflow therethrough. The valve lll responds to lowered viscosity of the fluid to permit continued flow of the warmed iiuid subsequent to its initial flow through the warming jacket, during which time the v'alvel5 re# mains closed.

The viscosity controlled unit as illustrated in i Figs. l and 2 comprises a housing i'- having therein va fluid pressure chamber il, provided at one side with a seat for the Valve I and at the opposite lside with a seat for the .by-pass relief valve i5. 4

Fluidunder'pressure enters the pressure chamber' i1 through the connection-i8. Projecting into thepressure chamber il is a friction tube I9, sometimesknown as a Venturi tube or metering tubehaving therethrough a tapered bore-20" communicating with -a passage 2i in the housing i6 through which the iluid under pressure may flow -more or less freely .inaccordance with its is forcedby pressure thereof vWithin tile chamber mined maximum and the length and size of the Venturi or friction tube bore 20 is designed to provide the normal range of back pressurevan'- ationvwithin' the normal range or viscosity change of the fluid at the-prevailing inlet pressure to the chamber I1.' l

To minimize A'possible cloggingl of. the minute entrance orifice 22, a' screen hood 23 encloses the y open end of the friction or Venturi tube 19.' Communicating with the tube passage 20 closely `ad..

jacent to theinlet orice 22 is -a branch duct 24 and continuing passage 25 inthe housingls` i through whichI fluid under existing pressure with- 'in the tube passage I9 is'admitted into an expansible and contractible chamber 26 behind the vpressure operated outlet `valve I4. The back pressure within the communicating'branch conduits 24-.25 equalizesfwith the back pressure within the Venturi orf-riction tube bore, 20 created by resistance. to flow =of the 'uid therethrough and iluctuates 'in unison therewith. Since a flow of liquid ofv high Viscosity through A the restricted passage; 20 of the tube I9 under influence ofpressure from thevchamber lI'I is resistd'to a greater extent than. flow of liquid The size and capacity of the inlet orifice 22, is proportioned to limit the flow to a. predeterof low viscosity therethrough, the pressure in the passages '2t- 25 and chamber 26 created by resistance to iiow in the passages will increase or decrease as viscosity of the iluid increases or decreases.

The passages 20-2I, leading from the chamber I 1 to the area rearwardly of the valve I 5 .are subjected to pressure through the inlet oriice 22 in accordance with the prevailing pressure in the chamber I1. When the valve I is in closed po sitionl the fluid iiowing through the passages -2I is discharged from the outlet end of the passages at zero resistance, or substantially so, and there is thus effected a pressure differential between the inlet to and the outlet from thel passages which is equal to the difference between .Y therrprressurre in the Vchamber I1 and zero, orsubstantially zero pressure,nat the outlet from the passages. However, when the valve I 5 is open and iiuid is flowing from the inlet chamber I1 past the valve I5 and around-the jacket 5 of the heat exchange unit there is established a constant pressure diierential across the inlet to and the outlet from the passages 20-2! which is equal to the pressure differential between chamber I1 and the area rearwardly of the valve I5 as established by a spring `21 and the particular shape of the valve'seating and seat surfaces.

In operation, when the engine is started and the iiuid pump begins to feed iiuid under pressure to the chamber I1, the valve It opens due tothe resistance of spring 2G' being weaker than the spring 21 which resists opening movement of the valve I5, and the valve I5 remains closed. Fluid :dow is then past the valve M through the inlet i and into the baiiled interior of the heat exchange unit. Assuming the fluid to be cold, pressure is rapidly built up in the chamber I'I due to resistance to flow of the lluid through the tortuous interior path of the heat exchange unit. At the same time, ow of uidthrough-the passages 2Ii-2I under pressure prevailing in. the

until the viscosity thereof reaches such a low point by reason of the iiuid becoming heated that the resistance to flow of uid through passages 2ll-2I is reduced to such an extent that the back or static pressure created by resistance to now and eiective on the rearward f ace of the valve I 4 through chamber 26 is less than that which is necessary, in addition to the resistance of the spring 26', to hold the valve I4 closed in opposition to the resistance to opening movement of the valve I5 effected through the spring 21. Under such conditions the valve I5 closes and the valve I4- opens. the interior of the heat exchange unit having been warmed by now of oil past the valve I5 and around the warming jacket 5. At this time ilow will be through the interior of the heat exchange unit,V and such iiown will continue until for one reason or another the viscosity of the iiuid increases to such an extent that the resistance to liow of uid through the interior of the heat exchange unit will cause a pressure to be built up in the chamber 26'which,

system, operate an electric switch, lactuate a starting or cut-ofi mechanism, or perform other functions than those pertaining directly to the circulatory systemv of the governing iiuid per se as in the prior applications.. The specic applichamber I1 creates more or less, back pressure and resistance to now in accordance with the viscosity-of the fluid. This back pressure, or static pressure, becomes eii'ective in the chamber 26 through the passages 2l-25, and augments the spring 26 in resisting opening movement of the valve I4. As this static pressure increases, the valve I4 is moved toward closed position which increases the pressure in the chamber I1, and when the combined closing effect oi.' the static pressure and the spring 26 on the rearward face of the valve I 4 becomes suillciently strong and is greater than the resistance of the spring 21 to opening movement of the valve I5 the valve III closes and the valve I 5 opens.` It will be understood that such action of the valves and associated parts takes place within a rela tively short space o! time from ,the beginning of operation of the motor and the uid pump. It will be further understood that the opening and closing movements of the-valves Il and I5 as just described take place gradually. and not with a snap action. s

When the valve Il is closed and the valve I5 is open as just described. there will be a constant pressure differential between the inlet orice 22 of the passages 20-2I and the-outlet vfrom such passages which is rearwardly oi' the l valve I5. Under these conditions, the back press ure, or static pressure effective in the chamber cation in the present instance is for regulation of the air flow through the heat exchange unit I by automatic adjustment of a series of shutters 30 4mounted contiguous to the heat exchange unit I.

In the embodiment shown in Figs. 1 and 2 the back pressure passage or cul-de-sac conduit 2,5 is

connected through a branch conduit with a pressure cylinder 3I, having therein a reciprocatory piston 32 operable against the yielding resistance of a helical spring 33. As the back pressure within the conduits 25 and in thepressure cylinder 3.I increases with increased viscosity of the fluid, the piston yields to the increased fluid pressure against the tension of the spring 33. 'I'his occurs as the fluid being circulated through the heat exchange unit I is cooled by the circulation of air. To reduce the air circulation through the radiator unit I the shutters 30 are closed toY 28 through the passages 24-25 likewise variesl in accordance with the' viscosity of the iiuid. Fluid iiowin'g past Ithe valve I5 will continue greater or less degree proportionate to such increase inthe viscosity of the iluid. Such adjustment of the air control shutters 33 is eil'ected by the store-described movement of the piston 32. The stem of the piston .is connected to a crank arm 3l having operative connection with a reciprocatory coupling bar 35 to which lever arms 36 carried by the shutters are inturn pivotally connected. Thus reciprocatory move- 4 ment lof the piston is transmitted to the cou-l Bling bar 35 by adjustment of which-the vshutters are adiusted in unison proportionately`to the degree oi' movement 'o1' the piston. 'I 'he piston isso connected to the shutters that outward movement of the pistonagainst the resistance' of its spring, which occurs under influence of increased back pressure incidental to cooling o! the iiuid and its increased viscosity, serves to proportion- Vately close the'l shutters. This reduces the air :circulation and its cooling effect. -Ytrai-y, an increase of temperature of the govern- On the coni'ng iifuid, with its consequent lowering 'of its viscosity, effects a' reduction of back pressure withinV the pressure cylinder 3l, thereby permitting return of the piston by the tensioned spring 323. Asthe piston returns, the shtuters are proportionately opened to permit increased airflowthrough the radiator yor'heat exchange unit to again cool the governing iiuid and increase its viscosity. Thus the air circulation is 'varied in direct proportion to uctuations of viscosity until a relatively balanced condition is achieved between this tcmperature of the governing fluid and its. consequent viscosity and the supply of cooling air circulated through this unit. At higher altitudes and increased speeds whereby the cooling eiiect of the air isincreased, the shutters are automatically proportionately closed to compensate Yfor the changed conditions. On the contraryat lesser speeds and lower altitudes, the shutters are proportionately opened to compensate Afor loss of air cooling influence. The air cooling -enect is thus automatically balanced under varying conditions with the viscosity of the governing fluid.

p While the operationsdescribed pertain more Yparticularly to airplane installation, for conditicning engine lubricant, it is to be understood that the heat exchange unit may be omitted and in lieuof engine lubricant circulated therethrough any fluid susceptible to viscosity change may be circulated through the unit l@ in a closed circuit by pump or other means, solely for governing purposes. Y In such event, the circulated governing :duid may besubjected to the temperature of a roorrrtoy be air conditioned, and the shutters lin such case may control the entry' to the room of either warm air from a heater or cool air from a refrigerating unit, or atmospheric air from outside the room. The operation 'and function Y would be the same.

l InFig. 3 there shown an installatiorrwhere-fV in. the'V viscosityv controlled device is separate from the heat exchange unit, but operatively connected to the air control shutters associated therewith.. However, in this embodiment the pressure cylinder 3l hs'been 'assembled in the'unit. I6

in lieu o f thep'essure controlled valve 15, and is thermal conditions to Which-the fluid is subjected and by which its viscosity is determined. As the fluid ytemperature vrises andV its Viscosity decreases, more air or other cooling'medium is admitted to compensate for the increased temperature of the `fluid and the lower viscosity, and as subjected to baclpressure inuence similarly toV that which eiefctive -on thelrearward face of the-valve u, 1 and 2; through the cul-desac conduitsznlandg.

Whereas Avar'flous thermostatic apparatus has beenubefore devised wherein the expansionv and contraction oflfa body of uid is utilized as the controlling factor, bythe present invention the fluctuations 'of viscosity of the governing fluid is'` utilized for thermo control purposes. By the operation described, a balanced relation isestablished between the viscosity of the fluid and the the viscosity increases under influence of clecreased temperature, the supply of air or cooling medium isI automatically decreased until a balanced relation is attained.

From the above description it will be apparent that there is thus provided a device of the character described possessing the particular features of advantage before enumerated as desirable, but which obviously is susceptible of modification in its form, proportions, detail construction and arrangement of parts without departing 'from the principle involve or sacrificing any of its advantages.

-While in order to comply with the statute, the invention hasA been described in language more or less specific as to structural features, it is to be understood that the invention is not limited to the specific features shown, but that the means and construction herein disclosed comprise the preferred form of several modes of putting the invention into eect, and the invention is therefore claimed in any of its forms or modlcations within the legitimate and valid scope of the appended claims.

Having thus described our invention, we claim: l. A heat exchange unit wherein lubricant is circulated under pressure and relative to .which a' current of air is directed for cooling the lubricant, means for creating a predetermined pressure drop in the lubricant being circulated under pressure, adjustable deflector means for the air currentv by adjustment of which the cooling effect of the. air upon the lubricant is regulated, and a pressure operated device responsive to uctuations of back pressure of the lubricant and resultant resistance to flow incident to changes of viscosity thereof at the point of predetermined pressure drop for automatically adjusting the air deeotor means to maintain the viscositypof the lubricant substantially constant, said pressure operated device including a conduit throughV which iiuid under pressure flows in proportion to the viscosity thereof, a pressure chamber communicating with the conduit in which'lubricant .back

pressure is developed in proportion to ow of lubricant through said conduit and pressure operated means controlled by uctuations oi back pressure inthe chamber. l

' 2. An oil cooler through which engine lubriated by resistance to ow of the lubricant in the' Atube incident to fluctuations of viscosity *of the lubricant, and an operative connection between the expansible and contractible chamber and the adjustable air deflector for automatically ad justing the deector in accordance with fluctuations of, viscosity of the lubricant.

s. A heat exchange una through which is circulated lubricant under pressure from an airplane engine and relative to which air is circu-4 lated incident to the travel of the airplane for cooling the lubricant, a shutter ,structure for regulating the cooling influence of the air upon the lubricant, and a viscosity controlled unit re-c a sponsive to fluctuations of viscosity 'of the lubriwhich lubricant under pressure flows in proportion to the viscosity thereof, a pressure chamber communicating with the conduit in which lubricant back pressure is developed in proportion to the flow of lubricant through said conduit, and pressure operated means controlled by the iluctuations of back pressure in the chamber.

4. An oil cooler through which engine lubricant is circulated under pressure, and wherein a cooling medium is circulated in relation thereto' for cooling the oil and thereby changingthe viscosity thereof, adjustable regulating means for the cooling medium by adjustment of which the cooling effect of the medium is varied to correspondingly vary the viscosity of the lubricant, and a viscositycontrolled unit through which a vportion only of the lubricant is passed including a pressure roperated actuator for the cooling medium, and regulating means therefor governed by fluctuations of back pressure of the lubricant incident'to changes of viscosityrthereof and resultant variation in resistance to lubricant flow.

5. A heat exchange unit through whichlubricant is circulated under pressure and relativeto which air is circulated for cooling the circulated lubricant and changing the viscosity thereof, adjustable deector means for varying the cooling' inuence of the air uponthe circulated lubricant, a viscosity controlled unit including a tube having a ,restricted orifice through whicha portion only of the lubricant is passed, a pressure actuator for the adjustable air deector communicating with the tube and governed by fluctuations of back pressure within the tube incidental to iluctuatiom of viscosity and resultant resistance to flow of the iuid passing therethrough.`

6. In a viscosity controlled apparatus a circulatory system through which a viscous governing fluid is circulated under pressure, thermal conditioning means for the governing uid for varying the viscosity thereof, adjustable thermal control means therefor, and a viscosity controlled -unit subject to iiuctuations of viscosity and`re.

sultant resistance to ilow of the governing uid effective to actuate the adjustable thermal control means in accordance with such fluctuations cosity is changed,-thermal conditioning control means, a viscosity controlled unit subject to iniluence of changes of viscosity of the governing fluid, including a governor for the thermal conditioning control means subject to influence of fluctuations of back pressure of the governing uid induced by changes of viscosity thereof and the resultant resistance to flow, said governor including a. friction tube and a restricted oriice through which the fluid flows more or less freely in accordance with varying viscosity thereof. a branch conduit communicating with the friction tubethrough which varying fluid back pressure is exerted in proportion to the viscosity of the fluid flowing through the friction tube, and pres'- `sure operated means controlled by the fluctuations of back pressure through the branch conduit.

8. .A heat exchange unit wherein lubricant is circulated under pressure and relative to which a current of air is directed for cooling the lubricant, lubricant iow pressure equalizing means. adjustable deiiector means for the air current by adjustment of which the cooling effect of the air tioned, and relativev to which a current of air is circulated for thermally conditioning theAcircu lated viscous iluid, adjustable shutter means regulating `the circulation of air relative to the heat exchange unit, a viscosity controlled unit automatically adjusting said shutter means in accordance with fluctuations of viscosity andl resultant resistance to flow of the viscous uid being` conditioned, said viscosity controlled unit including la tube through which the viscous fluid ows uni der pressure, a restricted inlet crice thereto, and

a cul-de-sac communicating with the tube inof back pressure of the governing fluid induced by changes of viscosity thereof and resultant resistance to ow. said viscosity controlled unit including a conduit through which uuid under pressure flows in proportion to the viscosity thereof, a pressure chamber communicating with the conduit i which lubricant back pressure is developed in proportion to the flow of lubricant through said conduit, and pressure operated means controlled by the uctuations of back pressure inthe chamber.

'7. A pressure circulatory system for a viscous governing iluid wherein the fluid is subjected to termediate the restricted inlet orifice and the outlet from such tube, in which back pressure is developed proportionately to the pressure of the liquid flowing through the tube, pressure oper' uid is thermally conditioned by circulation of a conditioning fluid relative thereto, regulating means for the conditioning fluid, and a viscosity controlled unit automatically adjusting said regulating meansin accordance with fluctuations of:

viscosity and resultant resistance to flow of the viscous fluid being conditioned, said viscosity controlled unit including a tube through which the viscous fluid flows under pressure, a restricted inlet orifice thereto. and a culde-sac communieating with the tube intermediate the restricted inlet orifice yand the outlet from s'uch tube, in which back pressure is developed proporionately tothe pressure of the liquid flowing through the tube, and pressure operated means controlled by the fluctuation of back prsure in the cul-de-sac in accordance with variations of viscosity of the liquid.

thermal, conditioning iniiufence by which its vis- 11.' A circulatory system for a viscous governmedium.

l5. A circulatory system for a viscous governy of viscosity of the governing uid incident to changes of viscosity and resistance to flow thereof, said controtmeans including a tube through `which the viscous fluid ows under pressure, a restricted inlet orice thereto, anda cul-de-sac communicating with the tube intermediate the restricted inlet orice and the outlet from such l tube, in Which back pressure is'developed proportionately to the pressure ofL the duid iiovving through the tubeI and pressure operated means controlled by the uctuation of back pressure in the cui-de-sac in accordance with variations of viscosity of the liquid:

i2. A viscosity controlled apparatus including a. chamber to which governing fluid subjectto fluctuation ofviscosity is supplied under pressure, a tube communicating with the chamber having apassage therethrough and a restricted orifice for'ovv of the governing duid, a cul-de-sac communicating with the passage intermediate the orifice and the discharge, outlet from said tube inwhioh back pressure is developed proportionate to the pressure of the fluid ilowing through the tube, and an associated device controlled. by ductuations of back pressure incident to changes of viscosity of the governing fluid.

v i3. The herein described method which includes circulating viscous iiuid under pressure relative to a conditioning 'medium whereby the viscosity of the uid is changed, and utilizing y'the uctuations of back pressure of the huid incident to changes of viscosity and resultant resistance to ovv thereof for varying the effect of the conditioning medium relative to which the uid is circulated.

11i. The herein described method including relatively circulating body of viscous fluid under pressure and a uid conditioningmedium where ,by the viscosity of the viscous iiuid is changed,

and utilizing the uctuations of. back pressure oi' the viscous huid incident to changes of viscosity and resultant' resistance to flowthereof for controlling the iioW of the fluid conditioning ing huid wherein the huid is subjected to thermal conditioning inuence by which. its viscosity is asoiec changed, a viscosity controlled' unit subject to changes of viscosity of the governing iiuid, an associated device to be actuated, and. pressure operating means therefor energized by uctuations of back pressure oi the governing huid.v

induced by changesof viscosity and resultant resistance to iiow, said pressure operating means including a conduit through which yuid underV -I pressure ilows in vproportion to the viscosity thereof, a pressure chamber communicating with the conduit in which 'lubricant baclr` pressure is' developed in proportion to the fiow of lubriated means controlled by the iiuctuations oi back pressure in the chamber.

16. A circulatory system i'or a' viscous fluid undei` pressure wherein the fluid is subject to change of viscosity, a member exteriorly of the circulatory system to be actuated in accordance with changeset viscosity of the fluid, a viscosity com.

trolled'unit subject to iniluence oi fluctuations of viscosity oi the iiuid including a' pressure actuator for said member controlled by fluctuations of back pressure of the fluid induced by changes of viscosity and resultant resistance to iioW, a conduit through which fluid under pressure ilows in proportion to the viscosity thereof,

and a pressure chamber in which the pressure actuator is` disposed communicating with the conduit and in which lubricant back pressure is developed in proportion to the ovv of lubriby changes oi viscosity and resultant resistance to ow, a conduit through which uid under pressure hows in proportion to the viscosity thereof, and a chamber in `which the'pressure' actuated regulator is disposed communicating with the conduit and in which lubricant back pressure is developed in proportion to the iio'w oi-lubricant through such conduit.

" f 1 f' l G. MANL JOSH C. SHAW. 

